(CNN) -- Dr. Jack Kevorkian, the Michigan pathologist who put assisted suicide on the world's medical ethics stage, died early Friday, according to a spokesman with Beaumont Hospital in Royal Oak, Michigan. He was 83.

The assisted-suicide advocate had been hospitalized for pneumonia and a kidney-related ailment, his attorney had said.

He had struggled with kidney problems for years and had checked into a hospital earlier this month for similar problems, his lawyer, Mayer Morganroth, said. He checked back into the hospital in the Detroit suburb on May 18 after suffering a relapse, Morganroth said.

Kevorkian, dubbed "Dr. Death," made national headlines as a supporter of physician-assisted suicide and "right-to-die" legislation. He was charged with murder numerous times through the 1990s for helping terminally ill patients take their own lives.

He was convicted on second-degree murder charges in 1999 stemming from the death of a patient who suffered from amyotrophic lateral sclerosis, commonly called Lou Gehrig's disease. He was paroled in 2007.

After his release, he said he would not help end any more lives.

Morganroth told CNN Friday that he was summoned to the hospital Thursday night, with doctors telling him "the end was near" for Kevorkian.

"The doctors and nurses were extremely supportive," Morganroth said. They played music by Kevorkian's favorite composer -- Bach -- in his room, and Kevorkian died about 2:30 a.m., Morganroth said.

Attorney Geoffrey Fieger, who was Kervorkian's lawyer on several assisted-suicide cases, described Kevorkian as a "historic man."

"He simply felt that it was the duty of every physician to alleviate suffering, and when the circumstance was such that there was no alternative, to help that patient to end their own suffering," Fieger said in a statement.

In an interview with CNN's Dr. Sanjay Gupta last year, Kevorkian said he had no regrets about his work.

In that interview, Kevorkian said that he had three missions in life and that he himself was not ready to die.

One of his missions was to warn mankind of "impending doom" that will come from the culture of overabundance.

"I'm not going to be too popular for that one," he said.

His second mission was to educate people about assisted suicide, and his belief that in states where assisted suicide has been legalized, it is not being done right. He believed that people shouldn't have to have a terminal condition in order to qualify for help in ending their own lives.

Kevorkian's third stated mission was to convince Americans that their rights are being infringed upon by bans on everything from smoking to assisted suicide.

In 2008, at the age of 80, he failed in a run for Congress in Michigan.